Tech note #1701: Garbage in, garbage out.

I set the Roomba about a mission to clean the floors and it kept getting stuck humping the edge of the bathroom scale. Kinda silly, counterproductive, and it left tire marks on the floor.

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... At least clean up after yourselves, geez.

After I noticed this, I thought of something…

The Roomba has a nice multitude of sensors that regulate its operation, but it can deal with failures on some of them by determining their data is bad and ignoring them. For instance, this …

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This is the front caster. Notice how it’s half black and half, well, sort of white?

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An infrared LED and phototransistor sit above it and count its rotations.

Sorry I didn’t get a before pic, as if you needed to see a hair clogged axle that badly, but yeah…

Here’s what it looks like disassembled and cleaned out. It had hair wrapped in it and it couldn’t spin. It can be easily pried up from an end and the axle pressed out.

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Now it spins freely.

So what was up with the bathroom scale and floor? The Roomba was hitting the edge and just starting to lift off the floor – the wheels were losing traction, but still both rotating, and the jammed caster with rotation sensor was being ignored by the firmware.

Thus, the system thought it was just rolling across empty floor.

So does it work now? Just after cleaning the caster and resetting the CPU, I restarted the cycle. Upon getting jammed in the laces of my boot, the Roomba promptly stopped and asked for assistance.

The underlying concept that’s valuable to see here is: garbage in, garbage out. When looking at any system, consider the fact that an assembly within will only work as well as its input. Verify correct input signals before you start chasing your tail forever.

And from now on, I’m putting away the scale before starting the Roomba. Well, it can’t dust under it anyway.

Aja FS1, the frame sync that roared

We have metric buttloads of these wonderful frame sync/video Swiss Army Knives in service. Here’s what’s inside. Failures are rare and seem to be limited to burned out front panel LEDs (not critical), power supplies, and fans.

This one was working but causing noise complaints due to fan bearing drama.

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Five volt muffin
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Pots?!
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HD-SDI interface

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The brawn
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The brains
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5 volt PSUs. Both identical.

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5 vdc @ 6 amps

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Before I un-bunnied it!

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Watch out for this yellow thread lock.

Yellow?!

I’m going to call this yellow thread lock “Wishful Thinking Thread Locker” because it didn’t stop the standoffs from backing right out of there. I’m familiar with the usual grades:
Purple: Low strength, formulated for small fasteners. Also good to use as just an anti-galling aid.
Blue: Medium strength, removable. Also useful to prevent fastener galling.
Red: High strength, impact driver and/or heating with a torch, *or* the effort of destructive little demon spawn children needed for removal. Still prevents galling too, I guess.

The elegant transmitter site

This is genuinely the nicest transmitter site I’ve ever seen.

I approve.

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Who's gonna enforce this?!
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Harris Platinum VHF DTV whirr emitter
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The lights are all green. I'm happy here

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Whose bright idea was this load off button??!!

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Some have expressed concern over the right angle turn up here, rest assured it's not causing any bad juju.

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Whole lotta Burk.
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About the only way to watch "The Real" without being subjected to pain

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Oh, guys, guess what?

You have been

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…. Trolled. 😉

You slackers.

Studies have shown that a major component to dust in the home and workplace is shed skin cells.

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Quit teabagging your lungs.

Humans shed tens of thousands of these keratinized dead cells every day from all surfaces of the external epidermis.

The dust that builds up in your electronic equipment and gets kicked back into the air by fans and air currents is no different.

Therefore,
If you leave your gear all packed with dust, you’re breathing cast off nutsack.

Maybe now you’ll keep your mission critical gear clean, you slackers.

🎶The best part of waking up… 🎶

🎶 … Is capacitor in your cup 🎶

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T minus three, two, one, LIFTOFF! We have LIFTOFF!!

Device in question: a Channel Master Chinashit ATSC tuner. Sadly, this is one of the better units available.

State of mind

*prepares to post politically motivated spiel about how this state are a bunch of idiots, based on voting results*

*remembers that this is Florida, so calling it a bunch of idiots would be totally pointless and redundant*

*shitposts instead*

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Read it and be puzzled... Why does the right one still exist?

Things I never understood

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Seems like it perfectly combines the disadvantages of a car and a motorcycle into one exotic, disappointing package.

Note that this one has no plate; it’s an unregistered Opa-Locka douchecasserole special.

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